(a) Field of the Invention
The present invention relates to an automotive torque distribution system, and in particular, to a torque distribution system capable of distributing engine torque to front and rear wheels without using a multi-disc clutch.
(b) Description of the Related Art
FIG. 1 shows a conventional torque distribution system including a rear propeller shaft 10 connected to a transmission (not shown), a front propeller shaft 20, and a torque transfer device 30 interposed between the rear and front propeller shafts 10 and 20.
The torque transfer device 30 comprises a transfer clutch 15 and an idle gear 12 integrally mounted on the rear propeller shaft 10, a transfer gear 22 mounted on the front propeller shaft 20, and a chain 31 connecting the idle gear 12 and the transfer gear 22. The transfer clutch 15 is engaged in order to fix the idle gear 12 to the rear propeller shaft 10 when there is a rotational speed difference between the front and rear wheels such that a portion of the driving torque of the rear propeller shaft 10 is delivered to the front propeller shaft 20 via the chain connection.
The rotational difference between the front and rear wheels is computed by a controller (not shown) on the basis of parameters detected by rear and front wheel speed sensors 19 and 29 such that the controller responsively generates and sends a control signal to an actuator 18 for engaging or disengaging the transfer clutch 15.
However, since the conventional torque distribution system adopts a multi-disc clutch, this increases the number of parts of the system assembly as well as the vehicle weight.
The present invention has been made in an effort to solve the above problems of the prior art.
It is an object of the present invention to provide a torque distribution system capable of contributing to the lightening of a vehicle weight and reducing the number of assembly parts of the system by replacing the multi-disc clutch with a simple friction clutch.
To achieve the above object, a torque distribution system for a four-wheel-drive vehicle comprises an idle gear mounted on one of a front or rear propeller shaft, a transfer gear mounted on the other propeller shaft, a chain connecting the idle gear and the transfer gear, a clutch coaxially mounted with the idle gear on the propeller shaft where the idle gear is mounted, and means for controlling the clutch so as to selectively engage and disengage the clutch. The clutch comprises an external drum integrally fixed to the idle gear and having an inner circumferential friction plane and an internal drum slidably mounted on the propeller shaft, and an outer circumferential friction plane such that the internal drum selectively slides into and engages with the external drum.